added information about using the code review tool to review code
diff --git a/doc/codereview-directions.txt b/doc/codereview-directions.txt
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+This file has some general information about how 971 does code reviews.
+
+We use Rietveld (<https://code.google.com/p/rietveld>) running in an app engine
+ app of ours. It is at <http://971code.appspot.com/>.
+
+[General Procedure]
+We try to code review all code before it gets checked in to svn. Code reviews
+ are also sometimes useful for getting feedback about documentation etc.
+First, somebody starts a code review and sends out emails to people asking them
+ to look. Then, other people look at it and make suggestions (in the form of
+ comments). The person who started the review (the owner of it) looks at the
+ comments and responds to them and/or changes their code and uploads new
+ versions for everybody to look at. Once all of the reviewers approve the code,
+ the owner checks it in and closes the code review (issue).
+
+[Reviewing]
+This is the section for people who have received emails about reviewing code
+ should look.
+The email that you receive will have a link to the issue (like
+ <http://971code.appspot.com/82001/>). Click on it to go to the issue page.
+ The most useful form of diff are the "Side-by-side diffs". Click the "View"
+ link in that column next to each file to look at it. After the first set of
+ comments, the "Delta from patch set" links are also helpful to see what got
+ changed so that you don't have to look at everything agin. While looking at
+ a diff, double-click on any line of code to leave a comment there. You can
+ also reply to existing comments. The web interface sometimes "eats" comments
+ right after you create/edit them. Refresh the page to fix that (don't just do
+ it again, or you'll end up with 2 identical comments). Once you are done
+ looking at all of the files and making comments, click the
+ "Publish+Mail Comments" link (at the top of each diff or on the left of the
+ main issue page) to send out your comments. You can also put general notes in
+ the "Message" box. If you think that it looks good, then put "LGTM" somewhere
+ in the message. The owner of the code review will keep looking at your
+ comments, making changes, and sending out more messages until it's finished.
+
+TODO(brians): add information about starting a review
+
+For more information about using Rietveld, see
+ <https://code.google.com/p/rietveld/wiki/CodeReviewHelp>.